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[wwwdocs] gcc-4.9/changes.html: Mention that LTO now generates slim objects
- From: Tobias Burnus <tobias dot burnus at physik dot fu-berlin dot de>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Gerald Pfeifer <gerald at pfeifer dot com>, Jan Hubicka <hubicka at ucw dot cz>, Richard Biener <rguenther at suse dot de>
- Date: Fri, 21 Mar 2014 10:16:12 +0100
- Subject: [wwwdocs] gcc-4.9/changes.html: Mention that LTO now generates slim objects
- Authentication-results: sourceware.org; auth=none
This patch mentions that -flto now generates slim objects. That's especially
relevant for static libraries as one can there run into surprises, if one
does not know about gcc-ar.
OK - or do you have a better suggestion?
Tobias
--- changes.html 8 Mar 2014 20:45:54 -0000 1.63
+++ changes.html 21 Mar 2014 09:10:32 -0000
@@ -65,6 +65,13 @@
<li>Function bodies are now loaded on-demand and released early improving
overall memory usage at link time.</li>
<li>C++ hidden keyed methods can now be optimized out.</li>
+ <li>By default, compiling with the <code>-flto</code> option now generates
+ slim objects files (<code>.o</code>) which only contain intermediate
+ language representation for LTO. Use <code>-ffat-lto-objects</code> to
+ create files which contain additionally the object code. To generate
+ static libraries suitable for LTO processing, use <code>gcc-ar</code>
+ and <code>gcc-ranlib</code> (requires that <code>ar</code> and
+ <code>ranlib</code> have been compiled with plugin support).</li>
</ul>
Memory usage building Firefox with debug enabled was reduced from 15GB to
3.5GB; link time from 1700 seconds to 350 seconds.